Positioning systems such as Global Positioning System (GPS) that measures the current location by receiving signals transmitted from satellites are now widely used. However, with a positioning system that uses satellite signals, it is difficult to detect a location in an indoor environment where signals from satellites cannot be received.
In addition to conventional navigation services, various services using location information, such as offering of content according to locations, marketing, behavior analyses, asset management, and safety planning, are now provided, and the importance of location information is increasing accordingly.
As a method of measuring a location in an indoor environment, indoor location measurement using radio beacons of Wi-Fi (trademark) or Bluetooth (registered trademark) is becoming popular (see Non-Patent Document 1, for example).
There also are various other suggested location measurement methods, such as Indoor Messaging System (IMES) using the GPS signal format (see Non-Patent Document 2, for example), autonomous location measurement using a gyro sensor or the like without any wireless component, and the use of visible light or a magnetic field distribution.